Fix SDK tools to respect cwd option

Core tools now properly use the cwd passed to createAgentSession().
Added tool factory functions for SDK users who specify custom cwd with explicit tools.

Fixes #279

packages/coding-agent/src/cli/file-processor.ts

@@ -21,7 +21,7 @@ export async function processFileArguments(fileArgs: string[]): Promise<Processe
 
 	for (const fileArg of fileArgs) {
 		// Expand and resolve path (handles ~ expansion and macOS screenshot Unicode spaces)
-		const absolutePath = resolve(resolveReadPath(fileArg));
+		const absolutePath = resolve(resolveReadPath(fileArg, process.cwd()));
 
 		// Check if file exists
 		try {